1. Field of the Invention:
Photoresist compositions, particularly a positive photoresist of high sensitivity and high resolution that is applied as film to substrates or microchips.
2. The Prior Art:
Polycarbonate photoresist materials are known. The prior art also discloses generation of strong protic acid by photolysis of onium salts. CRIVELLO et al. (U.S. Pat. Nos. 136,102; 4,307,177) have previously reported the photodecomposition of polycarbonate in the presence of onium salts and water. The present invention works in the absence of water and represents the main chain analog of WILLSON et al.'s pendant-group carbonate photoresist. (See WILLSON et al. "Indroduction to Microlithography," page 152 et. seq., American Chemical Society, (1983)). Water is detrimental to the sensitivity of photoresists.
The prior art, also, discloses polycarbonate positive electron beam resists. However, the present positive resists have the advantage of higher sensitivity to the ultraviolet and visible radiations, and lesser sensitivity to oxygen and other singlet or triplet quenchers. Such resists have good potential for imaging in the fabrication of microelectronic devices, printing plates, and the like.
Additional prior art references are being submitted separately in an Information Disclosure Statement.